1. Field
The present disclosed embodiments relate generally to wireless communications, and more specifically to roaming in the context of CDMA2000 and GPRS systems.
2. Background
Wireless subscribers may desire to use their wireless terminals in conjunction with wireless systems other than their home systems to obtain access to services using their existing subscriptions. Access to these services may be independent of their normal wireless terminals, through wireless systems other than their home systems. This may occur, for example, when the subscriber is roaming outside the service area of their home system. Accordingly, manufacturers and system operators desire to allow subscribers to receive services using their terminals and subscriptions via a system which may not be the subscriber's home system, provided that the terminal and the serving system are compatible.
Serving roaming subscribers can be difficult even when the serving system and home system employ identical technologies. When the serving system uses an air interface that differs from that used in the subscriber's home system, interworking between these systems is typically performed due to fundamental differences in message protocols, call models, et cetra. This interworking can be achieved via an Interworking and Interoperability Function (IIF).
One example of an IIF is described in US Patent Application 2002/094811 A1 to Bright et al. entitled “Interworking and Interoperability of GPRS Systems With Systems of Other Technology Families.” US Patent Application 2002/094811 A1 provides a GPRS interworking and interoperability function (IIF) interposed between a serving GSM/GPRS wireless system and a second wireless system of a different technology family. The IIF allows a mobile station homed to the second wireless system to operate in the GSM/GPRS system. According to US Patent Application 2002/094811 A1, telecommunications system components are provided that allow interworking and interoperability of a serving GSM and/or GPRS system with certain “domestic wireless” systems. For example, a mobile station homed on such a domestic wireless system, but registered with the serving system in a GPRS-only mode, may receive services from the serving system. US Patent Application 2002/094811 A1 mentions that the term “domestic wireless” (DW) is intended to refer to non-GSM systems compatible with ANSI or equivalent standards for TDMA, CDMA, and analog cellular systems, as generally used in North America, or compatible with other similar systems.
Although US Patent Application 2002/094811 A1 acknowledges the need for an IIF allows a mobile station homed to a CDMA wireless system to operate in the GSM/GPRS system, US Patent Application 2002/094811 A1 does not discuss an IIF adapted for CDMA2000/GPRS roaming scenarios when the terminal is using Mobile IP or Simple IP. US Patent Application 2002/094811 A1 fails to provide sufficient information, direction or guidance regarding how an IIF could be constructed that would allow a mobile station homed to a CDMA2000 wireless system could operate in the GSM/GPRS system, when the terminal is using Mobile IP or Simple IP. For example, US Patent Application 2002/094811 A1 fails to provide any details regarding what modules would be needed to implement such an IIF, how the modules would be interconnected, timed and controlled so as to obtain the specific operations needed to implement such an IIF.
Thus, there is a need in the art for a general architecture can be adapted for CDMA2000/GPRS roaming scenarios, such as, GPRS foreign mode with Mobile IPv4, GPRS foreign mode with Simple IPv4 or IPv6, CDMA2000 packet data foreign mode with Mobile IPv4, and CDMA2000 packet data foreign mode with Simple IP, Mobile IPv4 or Mobile IPv6. It would be desirable to enable communication between a CDMA 2000 packet data system and a GPRS system, when a CDMA 2000 packet data native subscriber using Simple IP, Mobile IPv4 or Mobile IPv6 roams to the GPRS system by supporting bearer connectivity between the GPRS and CDMA 2000 packet data system. Similarly, it would also be desirable to enable communication between a GPRS system and a CDMA 2000 packet data system when a GPRS native subscriber roams from the GPRS system to the CDMA 2000 packet data system using Simple IP, Mobile IPv4 or Mobile IPv6 by supporting bearer connectivity between the GPRS system and the CDMA 2000 packet data system.